Stock feeding means for automatic machine tools



Oct. 8, 1940. s. BAXENDALE 2,216,572

STOCK FEEDING MEANS FOR AUTOMATiC MACHINE TOOLS Filed Sept. 12, 1938FIGJ.

INVENTOR SAMUEL BAXENDALE ATTORNEYS Patented Oct. 8, 1940 PATENT OFFICESTOCK FEEDING MEANS FOR AUTOMATIC I l i TOOLS Samuel Baxendale,Dearborn, Mich. Application September 12, 1938, Serial No. 229,573

Claims.

The invention relates to stock feeding means for automatic machine toolsand more particularly to that type in whichthe stock is gripped duringthe feeding movement by a surrounding collar which is'tilted forclamping engagement.

Figure 1 is a longitudinal section showing my improved feeder asarranged within the hollow spindle of the machine tool;" 1

Figure 2 is a similar view or amodified construction;

Figure 3 is an end elevation of Figure 2;

Figure 4 is a longitudinal section at right angles to Figure 2;

Figure 5 is a view similar to Figure another modification;

Figure 6 is an end elevation thereof;

Figure 7 is a section illustrating a modified construction of thegripping collar.

The principle underlying stock feeding devices of the above mentionedtype is that a collar which surrounds and loosely fits the stock barwhen in a plane perpendicular to the longitudinal axis of the bar will,if tilted at an angle, form a gripping engagement. It is, therefore,essential in the construction of a feeder that the collar should beautomatically tilted when moved in the feeding direction and released toassume a plane perpendicular to the axis during movement in the oppositedirection. One method for tilting the collar which has heretofore beenused is to provide an inclined abutment adjacent thereto which duringthe initialforward movement of the feeder, bears only on one side of theaxis of the collar. This is generally effective, but its action is notpositive for it is dependent upon the inertia of the collar and at timesit will merely slide the collar over the stock bar without gripping thesame. Another 1 showing ,method is to form the collar of unequal crosssection on opposite sides thereof so that centrifugal force may tend toturn it at an inclination to the axis. This also is non-positivedepending upon the angular velocity and other variable factors.Stillanother method is to press the collar against the inclined abutmentby a coil springwithin the feeder and surrounding the stock bar. Withthis there is nothing to insure that the pressure of the.

spring will tilt the collar, it depends upon the point of contactbetween the spring and the collar in relation to the point of contactbetween the collar and the abutment. It sometimes has the opposite fromthe desired effect, tending to move the collar into a planeperpendicular to the axis.

It is the primary object of the present invention to obtain aconstruction in which the collar is subjected to a tilting forcesufficient to insure a 5 gripping action whenever the feeder is movedforward. This'I have accomplished by subjecting the collar to resilientpressure definitely located to be at all times spaced from the point ofbearing of the "actuating member thereon. Various specific constructionswill accomplish this purpose. Thusas shown in Figure 1, A is the hollowspindle through which the stock is to be fed. B is an actuating tubularmember within this spindle having an internal shoulder C for bearingagainst a tubular bushing D having an inclined forward end E. F is thefeed collar located adjacent to the inclined face E. G is a pinprojecting forward from the member D and engaging an aperture in thecollar F to form a rotative coupling therewith. H is a pin or lugprojecting forward from the collar F at a point preferably diametricallyopposite the pin G, and I is a coil spring engaging this pin or lug andbearing with its opposite end against a cap J which is threadedlyengaged with the member B. The member D is also preferably held fromrotation within the member B by suitable means, such as the screw K.With the construction just described the pressure of the spring I isalways located diametrically on the opposite side of the collar from thebearing of the actuating member, so that there will be a positivegripping of the stock bar whenever the feeder moves forward.

With the modified construction shown in Figures 2 to 4 the member Dismilled to form the forward inclined face E between forwardlyprojecting furcations L. The collar F is also fiattened on its oppositeside to fit between these furcations which serve to prevent any relativerotary movement. At the forward end of the furcations there are formedshoulders M for the seating of an annular'member N which may be securedto its seat by peening over the end of the furcations, as indicated atO. A lug or pin N on the member N is located opposite the low side ofthe inclined face E and serves to hold a coil spring I, which bearsagainst the collar F. This: construction will, therefore, function thesame as that previously described. 50

In Figures 5 and. 6 another modification is shown comprising a pushermember P which has an inclined forward face P. Q is. a resilient member,preferably a sheet metal stamping, which is attached at Q to one side ofthe member P projecting forward therefrom and then return-bent to bearagainst the collar F This collar is not therefore rotatively coupled tothe member P, but the point of bearing thereon of the resilient member Qis located to be diametrically opposite from the advance end of theinclined face P. This will insure the positive gripping action.

The gripping collar is usually formed with parallel frontand rear facesand with its central bore perpendicular to these faces, Where it isdesired to use the feeder on finished bars of stock the corner betweenthe face of the bore and the radial faces may be rounded so as to avoidany marking. Where, however, the feeder is used upon unfinished stockthe firmness of the grip may be increased by having a sharp edge. A

still better gripping construction may be formed as shown in Figure 7,where the radial faces F of the collar are inclined to the axis orslightly coned. Also, the bore through the collar may be slightlyundercut as indicated at B so as to form acute-angled edge portions Sfor biting into the stock bar. I

What I claim as my invention is:

1. A stockfeeding device comprising a tubular actuating member having aforward face inclined to the longitudinal axis, a symmetrical collararranged adjacent to said inclined face, and means for resilientlypressing said collar toward said inclined face located to bear only at apoint laterally spaced from the advanced portion thereof.

2. A stock feeding device comprising a tubular actuating member having aforward face inclined to the longitudinal axis, a symmetrical collararranged adjacent to said inclined face,

and means for resiliently pressing said collar against said inclinedface located to bear only at a point substantially diametricallyopposite the advanced portion of said face.

3. A stock feeding device comprising a rotary tubular actuating memberhaving a forward face inclined to the longitudinal axis, a symmetricalcollar adjacent to said inclined face, means for preventing relativerotation. of said collar and actuating member, and resilient means forpressing against said collar locatedwith respect to the same to bearonly at a point substantially diametrically opposite from the advancedportion of said inclined face.

4. A stock feeding device comprising a rotary tubular member having aportion of its forward face in advance of other portions thereof, asymmetrical collar adjacent to said forward face, and resilient meanslocated with respect to said pusher to press rearwardly against saidcollar only at a point opposite said advanced portion of said forwardface.

5. In a device of v the class described, a stock feeding tube, means forslidably supporting bar stock axially within the tube, and stockgripping means in the tube to positively feed the stock with the tube inone direction only, said gripping means including a ring looselyencircling the stock, an abutment in the tube engageable with arelatively small section of the ring to tilt the same on the stock,- anda spring engageable with an opposite face of the ring and exerting aforce of compression on said ring to maintain in tilted stock grippingposition when the tube is moved in said one direction.

SAMUEL BAXENDALE.

